Sheng Li, Eiichi Fukuyama
Abstract Nanoscale gouge particles are common products during both rock friction experiments and natural fault slip. However, the frictional wear mechanisms of nanoscale gouge particles and their role in the evolution of fault shear strength remain poorly understood. Therefore, we employed the molecular dynamics method to simulate a series of nanoscale single‐particle wear processes in α ‐quartz sandwiched by two rough surfaces composed of spherical asperities. We explored the effects of asperity interval, particle size, contact configuration and the normal force on the wear damage and wear volume of gouge particles, as well as the influence of particle wear damage mode on the friction coefficient. We observed that higher normal forces could induce particle breakage over shorter loading distances, and the particles underwent three wear stages: stable, sub‐stable, and fracture stages. At stable stage, the wear volume increased linearly with loading distance. Sub‐stable stage was characterized by superliner wear volume growth. The wear volume in both stable and sub‐stable wear stages could be predicted by tangential shear work, as the shear work scaled well with the wear volume. Finally, we measured the critical loading distance until particle fracture. The particle size, normal force and contact configuration could significantly influence the lifetime of α ‐quartz gouge particles, and particle fracture could lead to an immediate increase in friction coefficient rather than a decrease. These findings could provide useful insights into the nanoscale friction and wear mechanisms of gouge particles, which will contribute to the understanding of the microscopic fault frictional behavior.